1. Field of the Invention
The invention relates to a hydraulic high-performance brake system for motor vehicles, especially passenger cars, with two brake circuits, in one of which, as a rule the front-axle brake circuit, the wheel brakes are exposed to a higher thermal load than in the other brake circuit, with a pump which, when activated, can produce, temporarily, at least in an interval of time following a braking operation, a stream of brake fluid which travels from the supply vessel to a tandem main cylinder, from this to the wheel-brake cylinders of the brakes subjected to a higher thermal load, and from these via the tandem main cylinder back again to the supply vessel, and which eliminates from the wheel-brake cylinders brake fluid heated during a braking phase and conveys cooler brake fluid into the wheel-brake cylinders from the supply vessel.
2. Description of the Prior Art
A brake system of this type is known from German Offenlegungsschrift No. 3,143,267.
The known brake system is designed specially for racing vehicles in which both the front-wheel brakes and the rear-wheel brakes are exposed to considerable thermal loads. It comprises two tandem main cylinders which can be actuated together and which are connected in parallel as regards the braking function and in series as regards the guidance of the brake-fluid circulation produced for the purpose of brake cooling. In the basic position of the two tandem main cylinders, the stream of brake fluid cooling the front-wheel brakes flows from the pressure outlet of the feed pump, via the front-axle outlet-pressure space of the first tandem main cy1inder, to the front-wheel brakes, from these to the front-axle outlet-pressure space of the second tandem main cylinder, and from this back to the supply vessel. Correspondingly, the stream of brake fluid cooling the rear-wheel brakes flows from the pressure outlet of the pump, via the outlet-pressure space assigned to the rear-axle brake circuit and belonging to one tandem main cylinder, to the rear-wheel brakes, and from these back to the outlet-pressure space assigned to the rear-axle brake circuit and belonging to the second tandem main cylinder, and from this back again to the supply vessel. Thus, in the known brake system, both the front-wheel and rear-wheel brakes of the vehicle are cooled as required in parallel flow paths of the stream of brake fluid.